Centrifuging apparatus

ABSTRACT

Centrifuging apparatus comprises a main centrifuging chamber having a bypass containing sensing means to sense when a certain flow is produced in the bypass as a result of sediment increase in the main centrifuging chamber, the main chamber having a movable wall movable to open a discharge aperture of the main chamber and to define a secondary centrifuging chamber with the bypass to maintain a centrifuging action when the main chamber is being discharged of sediment.

United States Patent [19] Carter CENTRIFUGING APPARATUS [75] Inventor: Terence Vernon Carter, South Nutfield, Redhill, England [73] Assignee: M.S.E. Holdings Limited, Sussex,

England [22] Filed: May 12, 1971 [2]] Appl. No.: 142,577

[52] US. Cl. 233/38, 210/368 [51] Int. Cl B04b 1/20 [58] Field of Search 233/16, 19 R, 19 A,

233/20 R, 20 A, 21, 22, 46, 47 R, 17, 7, 29, 27, 35, 41, 38; 210/368 [56] References Cited UNITED STATES PATENTS 3,494,544 2/1970 Thylefors 233/19 R 3,623,657 11/1971 Trump 3,519,200 7/1970 Nilson 233/19 R 51 Sept. 25, 1973 3,255,958 6/1966 Simon 233/20 R 3,167,509 1/1965 Steinacker i 233/20 R 3,371,859 3/1968 Lyskovtsov 233/47 R 1,873,185 8/1932 Clark 233/7 Primary Examiner-George H. Krizmanich Att0rneyWaters, Roditi, Schwartz & Nissen [57] ABSTRACT Centrifuging apparatus comprises a main centrifuging chamber having a bypass containing sensing means to sense when a certain flow is produced in the bypass as a result of sediment increase in the main centrifuging chamber, the main chamber having a movable wall movable to open a discharge aperture of the main chamber and to define a secondary centrifuging chamber with the bypass to maintain a centrifuging action when the main chamber is being discharged of sedimerit.

11 Claims, 2 Drawing Figures CENTRIFUGING APPARATUS BACKGROUND OF THE INVENTION This invention relates to centrifuging apparatus and is particularly applicable to clarifiers for clarifying fluid from machine tools.

In the machine tool field, considerable quantities of machine tool coolant and lubricant fluid are used each day in any factory of significant size and this creates a problem in the handling of the used fluid and in particular in its cleansing for reuse, where one is dealing with fluid continuously flowing from machine tools.

It is an object of the invention to provide apparatus which can be designed to deal with this cleaning problem substantially without the need to regulate the flow of the fluid from a machine tool and which can dispose readily of the sludge accumulated by the cleaning action.

It will also be appreciated that, in the cleaning of fluid from sources such as machine tools, centrifuged material builds up in the centrifuging chamber until such an amount of the sediment is reached that the proper functioning of the clarifier is impaired and the centrifuge must be stopped for cleaning. However, it is not always possible to ascertain the correct moment for stopping the clarifier, and even if it were, the problem would remain of what to do with still supplied fluid.

The invention according to one embodiment can also provide a centrifuging SUMMARY OF THE lNVENTION An apparatus from which, preferably, an indication can be derived of when an excessive build-up of centrifugal material occurs, and, in particular, with which the flow of fluid supplied to the apparatus can be maintained when an excessive amount of sediment forms in the apparatus.

According to the invention there is provided a centrifuging apparatus comprising:

means defining an inlet for a mixture having components of different specific gravities;

means defining an outlet for the component of lesser specific gravity of said mixture;

a first rotatable wall structure defining an internal space communicating with said inlet and said outlet;

a second rotatable wall structure coaxial with and encircling said first structure, said second structure defining an outer wall portion of a first centrifuging chamber communicating with said outlet and also defining for said chamber a discharge aperture for discharging the component of greater specific gravity accumulated at said outer wall portion; and

a third wall structure displaceable relative to the first and second structures and having a first operative position in which said third wall structure closes said discharge aperture and permits communication between said inlet and said first chamber and a second operative position in whcih said aperture is open and said third wall structure engages said first wall structure to define therewith a second centrifuging chamber into which said inlet opens. Preferably, said first rotatable structure defines for said first chamber a bypass from said inlet tp said outlet and adapted to receive an increasing amount of mixture from said inlet as the centrifuged component of greater specific gravity increasingly constricts communication between said inlet and said first chamber. There may be sensing means within said bypass to sense fluid within said bypass to give an indication of excessive sediment in the first chamber.

Preferably, said sensing means will be provided to initiate the discharge mode, but this is not necessary; for example a timer might be provided to initiate the discharge mode at preselected times.

A preferred embodiment comprises a static portion and first and second independently rotatable portions. The static portion defines at least a portion of said inlet, the first-mentioned chamber is defined between the first rotatable portion and the, surrounding second rotatable portion, and the bypass is defined within the first rotatable portion. The movable wall portion is movable axially of the rotatable portions between a first position closing an aperture at the base of the second rotatable portion and a second position closing an aperture at the base of the first rotatable portion and severing communication between the inlet and the first-mentioned chamber. The first portion diverges towards the movable wall portion and/or the movable wall portion diverges towards the first portion so that a subsidiary centrifuging chamber is defined in the second position. Sensing means is disposed by the bypass. Any suitable flow sensing means may be employed; by way of example these means may be a resonant ultrasonic system the oscillation of which is interrupted by a predetermined flow in the bypass.

DESCRIPTION OF THE DRAWINGS For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:

FIG. 1 is a partially cut-away view of a clarifier; and

FIG. 2 is an axial partial cross-section of the clarifier of FIG. 1, the right-hand section of FIG. 2 illustrating the clarifier in its centrifuging mode of operation and the left-hand section of FIG. 2 illustrating the clarifier in its discharging mode.

The illustrated clarifier comprises, basically, a static structure, first and second rotatable structures and an axially movable and rotatable bottom wall member associable with both rotatable structures.

The static structure comprises an inlet tube 1 through which extends a draw bar 2 axially displaceable by means, for example, of a hydraulic actuator. The lower end of the draw bar rotatably supports the bottom wall member 3 carrying at its periphery upper and lower annular seals 4 and 5 respectively. The wall member 3 is of generally conical shape and its bearings 6 are cooled and lubricated by lubricant flowing along the path indicated by arrows. The wall member 3 is also supported by the tube 1 via rubber bearing 7 which is lubricated by clean fluid under pressure through pipe 44. The inner conical surface of the wall member 3 carries vanes 8 the upper ends of which support .a tubular member 9 having an outer surface splined or keyed at 10 to engage with the inner surface of a tubular portion 1 1 of the first rotatable structure 12 of the clarifier. In-

. stead of the splined or keyed coupling the structure 12 open at its lower end and opening at its upper end at an annular outlet 16 containing impeller vanes 17. the lower end of the structure 12 is formed with a frustoconical portion 18 having an annular peripheral ring 19 to engage seal 4, as illustrated at the left-hand section of the figure. When so engaged, the portion 18 defines with the wall member 3 a centrifuging chamber 22 communicating with the inlet tube 1. Separation is assisted in chamber 22 by conical disc or discs 45.

A resonant sensor is provided to sense flow in passage 15. This sensor is an ultrasonic resonator including two tubes which pass through the inlet tube 1 into the passage where the open ends of the two tubes face each other. One of these tubes is visible in the figure and is denoted 25. When an appreciable flow exists in passage 15, the ultrasonic oscillations normally passing between said open ends are interrupted, the oscillations cease and the sensor emits a signal.

The second rotatable structure 26 is mounted on the first structure 12 by bearings 27 and 28. The lower portion of the structure 26 constitutes a centrifuge bowl 29. The bowl 29 has an aperture 30 at its lower end, an annular outlet 31 to a fluid collector at its upper end, the outlet 31 containing diffusion vanes 32, and a helically extending rib or ribs 33 on its inner wall. The bowl 29 defines a main centrifuging chamber 34 with the first rotatable structure 12, this chamber containing vanes 35 attached to the first rotatable structure 12.

The structure 26 is adapted to be driven from the motor shaft via a controllable, e.g., electromagnetic, clutch 36 and a belt drive 37. The structure 26 also carries a brake disc having braking means 39. Braking may also be effected in the drive, for example by an electromagnetic brake/clutch 43.

The braking means 39 and the clutch 36 or the brake/clutch 43 are operable in response to the ultrasonic sensor.

In normal operation, the clarifier is in the condition illustrated at the right-hand side of the figure with the structures 12 and 26 rotating together at the same speed and with the wall member 3 closing the aperture 30 of the bowl 29. Contaminated fluid, from a machine tool for example, enters the inlet tube 1 and passes therefrom via a vortex in wall member 3 into the chamber 34 where contaminating particles are centrifuged onto the inner wall of the bowl 29 and build up as sludge 40, whilst clarified fluid passes through outlet 31. Eventually the build-up of sludge will constrict an inlet 41 to the chamber 34, causing some of the fluid to flow through passage 15 and thus bypass the chamber 34. This bypassing flow will cause the ultrasonic sensor to emit a signal.

This signal will operate a relay to initiate a rapid discharging operation. The first step of this operation is the lifting of the draw bar 2 to lift the wall member 3 until its seal 4 contacts ring 19 and seals-off chamber 34. Centrifuging will continue in the chamber 22, the clarified fluid passing from outlet 16 to outlet 31 and drawing excess fluid from the chamber 34. Balance is assisted by diffusion vanes 32. Secondly, the clutch 36 is operated to remove drive from the structure 26 and finally the braking means are operated to brake the bowl 29, thus ejecting sludge 40 downwardly and through the now-open aperture 30. This ejection is assisted by the helical rib or ribs 33.

I claim:

l. A centrifuging apparatus comprising:

means defining an inlet for a mixture having components of different specific gravities;

means defining an outlet for the component of lesser specific gravity of said mixture;

a first rotatable wall structure defining an internal space communicating with said inlet and said outlet;

a second rotatable wall structure coaxial with and encircling said first structure, said second structure defining an outer wall portion of a first centrifuging chamber communicating with said outlet and also defining for said chamber a discharge aperture for discharging the component of greater specific gravity accumulated at said outer wall portion; and

a third wall structure displaceable relative to the first and second structures and having a first operative position in which said third wall structure closes said discharge aperture and permits communication between said inlet and said first chamber and a second operative position in which said aperture is open and said third wall structure engages said first wall structure to define therewith a second centrifuging chamber into which said inlet opens.

2. An apparatus as claimed in claim 1, wherein said first rotatable structure defines for said first chamber a bypass from said inlet to said outlet and adapted to receive an increasing amount of mixture from said inlet as the centrifuged component of greater specific gravity increasingly constricts communication between said inlet and said first chamber.

3. An apparatus as claimed in claim 2, and comprising sensing means for sensing fluid flow in said bypass.

4. An apparatus as claimed in claim 3, wherein said sensing means are a resonant ultrasonic system which has a resonant state until a certain flow exists in said bypass.

5. An apparatus as claimed in claim 2, wherein said third structure is movable axially of said first and second structures and in said second operative position is within the space encircled by said second structure and defines therewith a continuously annular discharge zone of said discharge aperture.

6. An apparatus as claimed in claim 2, wherin said second structure defines said outlet in the form of an annular outlet and said first structure defines a further, outwardly opening, outlet opening into said annular outlet.

7. An apparatus as claimed in claim 1, wherein at least one of said first wall structures and said third wall structure diverges towards the other to define said second chamber.

8. An apparatus according to claim 1, and comprising a stationary structure defining said inlet and a movable member axially displaceable within said stationary structure and carrying said third wall structure.

9. An apparatus as claimed in claim 1 and comprising means for changing the speed of said first chamber.

10. An apparatus as claimed in claim 1, wherein the first and second wall structures are independently rotatable and the second wall structure has braking means.

11. An apparatus as claimed in claim 1, wherein said first chamber has a peripheral wall having a helical rib to assist the discharge of material from that wall. 

1. A centrifuging apparatus comprising: means defining an inlet for a mixture having components of different specific gravities; means defining an outlet for the component of lesser specific gravity of said mixture; a first rotatable wall structure defining an internal space communicating with said inlet and said outlet; a second rotatable wall structure coaxial with and encircling said first structure, said second structure defining an outer wall portion of a first centrifuging chamber communicating with said outlet and also defining for said chamber a discharge aperture for discharging the component of greater specific gravity accumulated at said outer wall portion; and a third wall structure displaceable relative to the first and Second structures and having a first operative position in which said third wall structure closes said discharge aperture and permits communication between said inlet and said first chamber and a second operative position in which said aperture is open and said third wall structure engages said first wall structure to define therewith a second centrifuging chamber into which said inlet opens.
 2. An apparatus as claimed in claim 1, wherein said first rotatable structure defines for said first chamber a bypass from said inlet to said outlet and adapted to receive an increasing amount of mixture from said inlet as the centrifuged component of greater specific gravity increasingly constricts communication between said inlet and said first chamber.
 3. An apparatus as claimed in claim 2, and comprising sensing means for sensing fluid flow in said bypass.
 4. An apparatus as claimed in claim 3, wherein said sensing means are a resonant ultrasonic system which has a resonant state until a certain flow exists in said bypass.
 5. An apparatus as claimed in claim 2, wherein said third structure is movable axially of said first and second structures and in said second operative position is within the space encircled by said second structure and defines therewith a continuously annular discharge zone of said discharge aperture.
 6. An apparatus as claimed in claim 2, wherin said second structure defines said outlet in the form of an annular outlet and said first structure defines a further, outwardly opening, outlet opening into said annular outlet.
 7. An apparatus as claimed in claim 1, wherein at least one of said first wall structures and said third wall structure diverges towards the other to define said second chamber.
 8. An apparatus according to claim 1, and comprising a stationary structure defining said inlet and a movable member axially displaceable within said stationary structure and carrying said third wall structure.
 9. An apparatus as claimed in claim 1 and comprising means for changing the speed of said first chamber.
 10. An apparatus as claimed in claim 1, wherein the first and second wall structures are independently rotatable and the second wall structure has braking means.
 11. An apparatus as claimed in claim 1, wherein said first chamber has a peripheral wall having a helical rib to assist the discharge of material from that wall. 